diff -r 17d242844fc9 -r 60bdcb9a7b94 src/java.rmi/share/classes/sun/rmi/transport/tcp/TCPConnection.java
--- a/src/java.rmi/share/classes/sun/rmi/transport/tcp/TCPConnection.java	Wed Nov 27 16:01:34 2019 +0000
+++ b/src/java.rmi/share/classes/sun/rmi/transport/tcp/TCPConnection.java	Thu Nov 28 13:48:25 2019 +0800
@@ -209,7 +209,10 @@
      * Close the connection.  */
     public void close() throws IOException
     {
-        TCPTransport.tcpLog.log(Log.BRIEF, "close connection");
+        if (TCPTransport.tcpLog.isLoggable(Log.BRIEF)) {
+            TCPTransport.tcpLog.log(Log.BRIEF,
+                    "close connection, socket: " + socket);
+        }
 
         if (socket != null)
             socket.close();